You said the throttle cable was worn out from friction and no other?
I am guessing your battery is fine.
You should wait for the new throttle before changing your controller. Make sure there are no errors before installing the new controller. Try to get the controller you already have installed working with the new throttle before trying the new controller.
Its the order of expense and operation I am concerned with. You could change the old controller only to find it still doesnt work.
There is a test you can do to test the throttle and controller.
If you purchase a variable 50k resistor pot (below) and put it on your already broke throttle cable. Some citation on the pot value by another member would be appreciated.
Unplug battery pack from controller.
Discard the broken twist throttle from the circuit, cut it off.
From the broken worn out wire still connected to the controller, Solder the red wire onto resistor pot pin 1. Solder white wire onto pin 2 and the black wire onto resistor pot pin 3. Pin numbers right to left, or left to right, it doesnt matter as long as the red and black are on the outside pins.
This should simulate the throttle fine and the 50k resistance should create enough resistance between the red and black and short the white and black when the resistor is low.
Just for testing this should be good enough.
Turn the pot all the way towards the black wire and switch the controller on holding the brake lever so the motor doesnt turn. Release the brakes switch and if there uis no movement turn the pot towards the red wire, have the brakes ready so you can stop the motor quickly and easily. Or make sure the wheel is off the ground.
Do all soldering with pack unpluged.
Never allow red and black to touch each other.
Test all voltages of between the red and black wire and anything over 5v is the wrong wire. There is a red wire that is used as a battery indicator that has full pack voltage. Beware of this.
If by chance the resistor pot works do not try to use it as your throttle unless you design it properly to spring back to zero throttle. You may have an accident using such a resistor pot as your throttle.